Hydraulic brake for dynamometers



Dec. 14 1926.

Filed Nov. 3, 1925 3 Sheets-Sheet 1 'INVENTGH. H (N me/L.

J &1

Dec. 14 1926. 1,610,830

G. H. WALKER HYDRAULIC BRAKE FOR DYNAMOMETERS Filed Nov. 3 1925 3 Sheets-Sheet 2 g NYENTOR Dec. 14 1926.

. G. H. WALKER HYDRAULIC BRAKE FOR DYNAMOMETERS Filed Nov. 3'. 1925 3 Sheets-Sheet 5 INVENTOR. gm w ww 5 09.0w

Patented twee. 14-, 11926.,

GEORGE HENRY WALKER,

HYDRAULIC BRAKE Application filed. November 3, 1925, Serial ,No.

This invention relates to hydraulic brakes or dynamometers for absorbing and measuring the power developed by rotating shafts and more particularly to improvements in the type of hydraulic brake or dynztmometer in which a rotor mounted upon a shaft is enclosed in an outer casing, vanes or pockets being formed both in the rotor and the casing in which the water circulates creating eddies or vortices which destroy power when the rotor is revolved.

The specification of my prior British Patent No. 249 19 of 1910 described an hydraulic brake or dynamometer of the type above referred to in which the vanes of the casing androtor are provided with passages for water or air, the water passages being utilized. to maintain a Continuous supply of fresh coolwaterto the brake, and the air passages to maintain atmospheric pressure atthe centre of the vorticesformed by the rotation of water in the brake. The specification No. 24949 of 1910 and the specifica- 'tions of other of our priorBritish patents,

also describe means for controlling the, outlet of water from the casing partly with the object of maintaining a suitable working temperature and partly with the object of controlling .the consumption of power.

According to'the present invention means are. provided for supplying all or a portion of. the water to thebrake or .dynamometer at a rate ofieed which is proportionate to the speed of. rotationof the shaft and also if desiredlfor recirculating the water'leav ing therotor through the water passages in the .vanes of the rotor.

The invention will be described with refierence to the accompanying drawings.

1 is .a front elevation of one form of the invention applied to a reversing type of 'dynam-ometer inwhich there are two sets of power absorbing; elements, one arranged to rotate clock-wise and the other anti-clockwise.

Fig. 2 is a longitudinal section of same.

Fig.3 isan end elevationot same.

Fig. 4: is. a front elevation otanother form of the invention, applied to a non-reversing type of dynamometer.

" Fig. 5 is an end elevation of same.

As shown in Figs. 1..to 3 the invention is applied to a reversing type of dynamometer in which there are two sets of power absorbing elements-the rotors el-one ar- FUR DYNAIVIOMETERS.

OF TWORCE$TER, ENG-LANE), ASSXGNOR T0 .HEENAN :35 FBOUDE LIIVIITED, 03E CHAPEL WALKS, IVJTAJEGFEtE ENGLAND.

66,670, and in Britain November 11 1924.

rangedto rotate in aclockwise direction and the other in a counter-clockwlse direction,

means being provided so that the supply of water can be cut oil "from one or other of the compartments as desired and the whole of" the power be absorbed in the other compartment. The main supply of wateris admitted to the caslng through an inlet valve 13 and a flexible pip branch one 6 connec compartments A e B connected to a ted to the two rotor In the form of the invention shown in F1gs 1 to 3 the centrlfugal efi'ect of the revolvingrotor A oi: whichever half of the dynamometer is absorbing power is utilized the casing where the pressure is" high to a part of the casing where the pressure is low and from which the rotor obtains its supply of water.

Each rotor A is hollow and is fitted with a gland a surrounding the Sl'1afhA throu which it candraw a suitable supplyof water from a co A further vents leakage of wate ment.

After entering the nipartment C "formed in the casing. gland a around the shaft A prer from this comparthollow rotor A the waterpasses through the holes a formed'in the vanes 01. the rotor so as to communicate with a point a in the power-absorbing pock ets a where under running cond1t1ons.flthe pressure is low. At

pockets a the'points a of the the pressure of the water due to centrifugal force is higher than at the points where the holes a enter into the pockets this pressure is transferred and between theroto-r A and the casing. D. The water is conveyed from this zone of higher water pressure through the ports or passages e to a valve E so arranged that the area for the passage of water through the ports'in the valve can stages from fully open to fully outlet side of this through the pas ment C in the casin suction.

be varied by gradual shut. The

V EtlVG COl'llHlU lllCtttGS sage c with the compartwhich feeds the rotor Th compartment G is fitted with a release valve F which conveniently be of the spring loaded p discharge waste w attern arranged to open ater to aitunnelF or to the space (Z similar device whenever the pressure of water in the rotor suction compartment rises above a predetermined figure. Under normal running conditions the rate at which water leaves the rotor suction compartment A is generally governed by the speed at which the rotation of the rotor induces a flow of water through the holes in the rotor vanes and the rate at which water enters this compartment is governed by the opening of the main inlet valve B. Thus when water enters the compartment in greater quantities than itleaves through the rotor suction, a pressure immediately builds up in the compartment and opens the release valve F, which may be replaced by an overflow weir or the like.

Between the inlet valve B and the rotor suction compartment a valve. G may be inserted if desired though such valve is not essential to the working of the invention. The valve G is normally kept closed by a spring 9 and is fitted with a cylinder and piston on one side of which connection is made by pipes g to that chamber (Z in which, when power is being destroyed, the water pressure is high, while the other side of the piston g is connected to the compartment- C from which the water is supplied to the rotor. Thus when the difference in pressure between the two sides of the piston 9 due to the destruction of power is sufficiently great to overcome the resistance of the spring 9, the valve opens. admitting fresh water to the chamber 0. This fresh water mixes with the water re-circulated through the rotor valve, and keeps the temperature of the brake or dynamometer within suitable limits.

Immediately upon the supply of power being removed from the shaft of the brake, however, the difference in pressure between the two sides of the piston g disappears, and the valve G closes under the influence of the spring 9, thus shutting off the supply of fresh water, preventing the dynamometer being unduly filled with water which would create a severe resistance to rotation next time the dynamometer should be started up. Figs. 4 and 5 show a non-reversing type of dynamometer with a single rotor. In the form of the invention illustrated in these figures water is fed to the power absorbing portions of the dynamometer by means of a separate pump driven by gearing or by direct coupling to the shaft of the dynamometer, a valve being interposed between the pump and the power absorbing cups of the dynamometer by which the amount of water entering the casing of the dynamometer can be regulated.

The supply of fresh water which is necessary for cooling purposes, is carried through flexible pipe B between a fixed portion of the dynamometer to a connection on the swivelling portion. The cool water passes from the pipe B to the suction side of a pump H wh ch may be of centrifugal or other type driven by chains h or other gearing, from the shaftiA of the dynamometer,

and therefore rotating at a speed which is into z'ucompart-ment of the casing of the.

dynamometer, from which holes drilled through the vanes of the non-rotating stator, carry the water into a point in the powerabsorbing pockets where under working conditions the pressure is low, as previously described. Ports are formed in the casing communicating with a. point where under working conditions the pressure of water is high to convey the water to an outlet valve F of similar construction to the outlet valve F described in connection with Figs. 1 to 3 by which the flow of water can be controlled. This valve F may conveniently discharge direct to waste through a funnel F or similar device. I

If desired a bypass pipe can be inserted to connect the discharge from valve F with the compartment 0, and allow re-circulation of the water as described with respect to Figs. 1 to 3.

In both the types of 'dynamometer described above, the load exerted by the dynamometer at any given speed is dependent upon the pressure of water which is maintained inside the power-absorbing compartment of the casing. If the resistance to the flow of water from the casing is high, it follows that the pressure of water and therefore the power consumed will be high. If the resistance to flow be diminished the power consumed will likewise diminish. In practice the adjustment of resistance is easily effected by regulating the outlet valve only, but a further means of regulation is offered in the case of the second form of the invention by manipulation of the valve K fixed between the pump discharge and the entry to casing.

What I claim as my invention and desire to protect by Letters Patent is 1. An hydraulic brake for dynamometers for measuring the power developed by rotating shafts comprising a casing, a rotor, a shaft within the casing on which said rotor is mounted, vanes formed on the rotor, vanes formed on the casing, and means automaticallv operated from the rotor shaft for supplying water to the rotor at a rate of flow which is proportional to the speed of rotation of the shaft. 7

2. An hydraulic brake for dynamometers for measuring the power developed by rotating shaft-s comprising a casing, a rotor, a shaft within the casing, on which said rotor is mounted, vanes formed on the rotor, vanes formed on the casing, means for supplying water to the rotor at a 'a-te of flow which is proportional to the speed of rotation of the shaft and means whereby the water leaving the rotor is recirculated through water passages in the vanes thereof.

3. An hydraulic brake for dynamometers for measuring the power developed by rotating shafts comprising a casing, a rotor, a shaft within the casing on which said rotor is mounted, vanes formed on the rotor, vanes formed on the casing, means for supplying water to the rotor at a rate of flow which is proportional to the speed of rotation of the shaft and means to promote a flow of water through holes formed in the rotor, the water being re-circulated from a part of the casing Where the pressure is high to a part where the pressure is low from which point the rotor draws its supply.

4:. An hydraulic brake for dynamometers for measuring the power developed by rotating shafts comprising a casing, a rotor, a shaft within the casing on which said rotor is mounted, vanes formed on the rotor, vanes formed on the casing, means for supplying water to the rotor at a rate of flow which is proportional to the speed of rotation of the shaft, means to promote a flow of water through holes formed in the rotor, the water being re-circulated from a part of the casing where the pressure is high to a part where the pressure is low from which point the rotor draws its supply and a valve to admit fresh water to the point of low pressure. 7 r i 5. An hydraulic brake for dynamometers for measuring the power developed by rotating shafts comprising a casing, a rotor, a shaft within the casing on which said rotor is mounted, vanes formed on the rotor, vanes formed on the casing and a pump driven by the rotor shaft for supplying the water to the rotor.

In testimony whereof I have hereunto set X h: '1. in] W eEoEoE H. WALKER. 

